A full year yes…usually the average life of a theme for code and compatibility updates is 1 year. Sometimes a theme needs to be completely rebuilt at least once a year, but generally a full year of updates pretty much guarantees all bugs or other adjustments have been achieved by that time and the theme should last past the year.
Copy & pasting code into the child theme’s style.css will go below the comment like this:
/* Add your style.css changes here
-----------------------------------------------------------------------------------*/
.yourclass {
background: #000000;
}
Regarding changing the width from boxed to full width with Preference could be done but it would definitely be significant recoding.
